The preparation of polymerizates from acrylic or methacrylic acid esters of various alcohols, in bulk as well as in solvent, has been known for a long time. For the latter method, hydrocarbons such as xylene or mineral oils, as well as solvents with functional groups, such as butanol, cyclohexanone, nitrobutane, acetic acid, and solvents having similar groups, can be used, for example. The polymers can then either be isolated directly from the solvents or be used in the form of the solution, as an aid in the preparation of lacquers based on epoxy resins, polyurethanes, chlorinated rubbers, polyvinyl chlorides, or nitrocellulose. Use of such polymer solutions in the lacquers can reduce frequently encountered disturbances and surfaces irregularities such as unaligned edges, orange-peel or egg-shell effects, or dimpling. The results generally are satisfactory, but the desired effect is not always achieved to an adequate degree, particularly when the polymerization was carried out in mineral oils or esters and the polymers are used without intermediate isolation. In addition, mineral oils and esters of fatty acids are basically undesirable as additives in lacquer components since they remain in the film after the drying of the lacquers and frequently are incompatible. These solvents can cause flow disturbances by floating to the surface, thereby forming fish eyes, and the like. When the acrylates are prepared in mineral oils, frequently products are obtained which are highly viscous, which may contain gel particles, which are difficult to handle, and which have an undesirably broad, undefined molecular weight distribution.
Thus, there has been a need for flow-promoting or leveling agents based on polyacrylates or polymethacrylates which do not have any negative influence on the finished coating due to the solvent. There has also been a need to find solvents in which the polymerizable acrylates or methacrylates remain easy to handle even at a concentration above 30%, especially 40%, and can be polymerized reproducibly on a technical scale under conditions of uniform temperature. Advantageously, the desired solvents act as reactive thinners that would be incorporated into a lacquer film itself in the manner that epoxy compounds, for example, can act as reactive thinners in epoxy lacquers.